A5010090048- Microtubule and mitosis dynamics
- RNA and protein synthesis mechanisms
- RNA modifications and cancer
- Genomics and Chromatin Dynamics
- Photosynthetic Processes and Mechanisms
- RNA Research and Splicing
- Advanced Fluorescence Microscopy Techniques
- DNA Repair Mechanisms
- Ubiquitin and proteasome pathways
- Nuclear Structure and Function
- Protein Structure and Dynamics
- Micro and Nano Robotics
- Digital Holography and Microscopy
- Cellular Mechanics and Interactions
- Protist diversity and phylogeny
- Peptidase Inhibition and Analysis
- 14-3-3 protein interactions
- Advanced Electron Microscopy Techniques and Applications
- Enzyme Structure and Function
- Plant Molecular Biology Research
- Advanced Materials and Mechanics
- Bacterial Genetics and Biotechnology
- Cellular transport and secretion
- Optical Coatings and Gratings
- Bacteriophages and microbial interactions
Princeton University
2015-2024
Princeton Public Schools
2021
University of California, San Francisco
2011-2013
Howard Hughes Medical Institute
2009-2013
Marine Biological Laboratory
2013
MRC Laboratory of Molecular Biology
2005-2010
Medical Research Council
2008
The crystal structure of the bacterial 70S ribosome refined to 2.8 angstrom resolution reveals atomic details its interactions with messenger RNA (mRNA) and transfer (tRNA). A metal ion stabilizes a kink in mRNA that demarcates boundary between P sites, which is potentially important prevent slippage mRNA. Metal ions also stabilize intersubunit interface. E-site tRNA 50S subunit have both similarities differences compared those archaeal ribosome. rationalizes much biochemical genetic data on...
The termination of protein synthesis occurs through the specific recognition a stop codon in A site ribosome by release factor (RF), which then catalyzes hydrolysis nascent chain from P-site transfer RNA. Here we present, at resolution 3.5 angstroms, crystal structure RF2 complex with its cognate UGA 70S ribosome. provides insight into how specifically recognizes codon; it also suggests model for role universally conserved GGQ motif catalysis peptide release.
Abstract Phase separation of substrates and effectors is proposed to enhance biological reaction rates efficiency. Targeting protein for Xklp2 (TPX2) an effector branching microtubule nucleation in spindles functions with the substrate tubulin by unknown mechanism. Here we show that TPX2 phase separates into a co-condensate tubulin, which mediates vitro isolated cytosol. TPX2-tubulin co-condensation preferentially occurs on pre-existing microtubules, site nucleation, at endogenous...
The mitotic spindle is constructed from microtubules (MTs) nucleated centrosomes, chromosome proximal regions, and preexisting MTs. Augmin, a recently identified protein complex, critical factor in MT-based MT generation Drosophila S2 cells. Previously, we one subunit of human augmin. Here, by using mass spectrometry, the full augmin complex 8 subunits show that it interacts with gamma-tubulin ring (gamma-TuRC). Unlike augmin-depleted cells, which defect spindle-mediated mostly compensated...
The mitotic spindle consists of microtubules (MTs), which are nucleated by the γ-tubulin ring complex (γ-TuRC). How γ-TuRC gets activated at right time and location remains elusive. Recently, it was uncovered that MTs nucleate from preexisting within spindle, requires protein TPX2, but mechanism basis for TPX2 action is unknown. Here, we investigate role in branching MT nucleation. We establish domain organization Xenopus laevis define minimal version stimulates nucleation, find unrelated to...
The repeating arrangement of tubulin dimers confers great mechanical strength to microtubules, which are used as scaffolds for intracellular macromolecular transport in cells and exploited biohybrid devices. crystalline order a microtubule, with lattice constants short enough allow energy transfer between amino acid chromophores, is similar synthetic structures designed light harvesting. After photoexcitation, can these chromophores excitation along the microtubule like natural or artificial...
Female meiotic spindles in many organisms form the absence of centrosomes, organelle typically associated with microtubule (MT) nucleation. Previous studies have proposed that these arise from RanGTP-mediated MT nucleation vicinity chromatin; however, whether this process is sufficient for spindle formation unknown. Here, we investigated a recently spindle-based pathway involves augmin, an 8-subunit protein complex, also contributes to morphogenesis. We used assay system which hundreds can...
Microtubules are nucleated from specific locations at precise times in the cell cycle. However, factors that constitute these microtubule nucleation pathways and their mode of action still need to be identified. Using purified Xenopus laevis proteins we biochemically reconstitute branching nucleation, which is critical for chromosome segregation. We found besides nucleator gamma-tubulin ring complex (γ-TuRC), effectors augmin TPX2 required efficiently nucleate microtubules pre-existing...
Microtubules (MTs) must be generated from precise locations to form the structural frameworks required for cell shape and function. MTs are nucleated by γ-tubulin ring complex (γ-TuRC), but it remains unclear how γ-TuRC gets right location. Augmin has been suggested a targeting factor is MT nucleation preexisting MTs. To determine augmin's architecture function, we purified
To understand how chromosomes are segregated, it is necessary to explain the precise spatiotemporal organization of microtubules (MTs) in mitotic spindle. We use Xenopus egg extracts study nucleation and dynamics MTs branched networks, a process that critical for spindle assembly. Surprisingly, new preferentially originate near minus-ends pre-existing MTs. A sequential reaction model, consisting deposition sites on an existing MT, followed by rate-limiting branches, reproduces measured...
Determining how microtubules (MTs) are nucleated is essential for understanding the cytoskeleton assembles. While MT nucleator, γ-tubulin ring complex (γ-TuRC) has been identified, precisely γ-TuRC nucleates a remains poorly understood. Here, we developed single molecule assay to directly visualize nucleation of from purified Xenopus laevis γ-TuRC. We reveal high γ-/αβ-tubulin affinity, which facilitates assembly Whereas spontaneous requires 8 αβ-tubulins, occurs efficiently with...
Mitotic spindles are composed of microtubules (MTs) that must nucleate at the right place and time. Ran regulates this process by directly controlling release spindle assembly factors (SAFs) from nucleocytoplasmic shuttle proteins importin-αβ subsequently forms a biochemical gradient SAFs localized around chromosomes. The majority MTs generated branching MT nucleation, which has been shown to require an eight-subunit protein complex known as augmin. In Xenopus laevis, can control through...